The dressing of a tool first serves to give the tool a surface geometry required for the machining of a workpiece.
A method is known from DE102012015846A1 in which a modification of the surface geometry is produced by additional movements when dressing on the tool, said modification having a constant value in the generating pattern at least locally in a first direction on the tooth flank and being given by a function f(x) in a second direction which extends perpendicular to the first direction. A method is known from EP1995010A1 and WO 2010/060596A1 of dressing a worm in a crowning manner over its width by changing the center distance during dressing. A method is known from DE19624842A1 and DE 19706867A1 in which a worm whose profile angle changes over its width is produced by a constant change of the position of the dresser with respect to the tool during dressing. Methods are likewise known from DE 102005030846A1 and DE 102006061759A1 in which a worm is manufactured by corresponding dressing kinematics either over its total width with a constantly modified profile angle or the profile angle is modified over the worm width. A two-flank dressing for twist-free generating grinding is known from Kapp, Effizient and produktiv mit technologischer Flexibilität, JOSE LOPEZ [Kapp, Efficient and Productive with Technological Flexibility, JOSE LOPEZ].
It must furthermore be taken into account that the tools used for the machining of workpieces within the framework of a gear machining process are subject to constant wear due to their high strain during gear manufacturing machining. The tools therefore have to be dressed again at regular intervals in order to be further able to produce workpieces having the desired gear geometry. The active surface of the tool is machined in dressing using a dresser to give said active surface the desired shape again.
The dressers used for dressing are typically designed for a specific macrogeometry of the tool and in particular for a specific diameter of the tool. However, the diameter of the tool is reduced by the repeating dressing processes. The dresser hereby no longer matches the tool after a certain number of dressing procedures so that unwanted deviations are produced in the gear geometry of the tool. With larger worm diameters and small diameter differences between the new tool and the diameter toward the end of use, deviations have previously been negligible with current tolerance specifications. With small tool diameters or large modules or a high number of starts, in contrast, the deviations have to be taken into account. In accordance with the prior art, either a plurality of dressers therefore have to be used for the different diameters of the tool could not be utilized over its complete diameter range.
It is the object of the present disclosure to provide an efficient method of producing one or more workpieces having a desired gear geometry.
In a first aspect, the present disclosure comprises a method of manufacturing one or more workpieces having a desired gear geometry by means of a suitably dressed tool, in which, after the carrying out of one or more machining steps, the tool is respectively dressed by a dresser before further machining steps are carried out at the same workpiece or at further workpieces. In accordance with the present disclosure, on a later dressing procedure, the relative position between the dresser and the tool changes with respect to a prior dressing procedure in addition to the smaller center distance resulting from the smaller tool diameter by a corresponding additional adjustment of the axes of movement of the dressing machine. In accordance with the present disclosure, the dresser is thus not simply only delivered more closely to the tool to take account of the tool diameter having become smaller due to the preceding dressing procedures. An adjustment of the axes of movement of the dressing machine rather takes place in addition to this reduction of the center distance.
The additional adjustment of the axes of movement of the dressing machine optionally takes place such that modifications of the gear geometry which are produced by the tool diameter having become smaller are at least partly compensated. The present disclosure thus takes into account that the dresser actually no longer exactly matches the tool due to the smaller tool diameter and at least partly and optionally completely compensates the modifications arising hereby by a corresponding setting of the axes of movement.
Alternatively or additionally, the additional adjustment of the axes of movement of the dressing machine can effect a change of the profile crowning produced during dressing with respect to a dressing without such an additional adjustment. The inventor of the present disclosure has recognized that influence can be taken on the profile crowning produced during dressing by the adjustment of the axes of movement of the dressing machine. Since the tool diameter which becomes smaller also results in an unwanted change of the profile crowning, this can be at least partly compensated by a corresponding adjustment of the axes of movement of the gear manufacturing machine.
Further alternatively or additionally, the additional adjustment can be selected such that a deviation of the gear geometry produced on the workpiece from a desired gear geometry is reduced and/or minimized. Unwanted modifications on the workpiece machined using the tool can thus in particular be reduced by the adjustment of the axes of movement during dressing.
Further alternatively or additionally, the additional adjustment can reduce or minimize a deviation of the gear geometry produced by the dresser on the tool. The setting of the axes of movement can in particular be calculated such that a desired geometry of the tool is reached as much as possible.
The method in accordance with the present disclosure in accordance with the first aspect can in particular be used to produce the same profile shape on the tool in every dressing procedure. The same profile shape on the tool can in particular nevertheless be produced despite the diameter of the tool becoming smaller due to the different setting of the movement of axes in accordance with the present disclosure during dressing. This optionally has the result within the framework of the machining method that unwanted modifications of the gear geometry resulting on the workpiece are reduced and optionally minimized.
In an alternative variant, the method in accordance with the first aspect can, however, also be used to specifically produce different profile shapes on the tool in the consecutive dressing procedures. These different profile shapes, however, may have the result in combination with a correspondingly adapted machining method that unwanted modifications of the gear geometry produced on the workpiece are reduced and minimized.
In accordance with a second aspect, the present disclosure comprises a method of manufacturing one or more workpieces having a desired gear geometry by means of a suitably dressed tool, in which, after the carrying out of one or more machining steps, the tool is respectively dressed before further machining steps are carried out at the same workpiece or at further workpieces. In accordance with the present disclosure, the profile angle of the tool is changed with respect to an earlier dressing procedure in a later dressing procedure, wherein the workpiece or workpieces is or are gear manufacturing machined after the later dressing procedure with a different profile angle of the gearing of the tool than after an earlier dressing procedure. The profile angle is respectively selected in a first variant of the second aspect such that a deviation of the gear geometry produced on the workpiece from a desired gear geometry is reduced or minimized. In a second variant, a stretching and/or compression of a modification produced on the tool by a modified dresser can be reduced or minimized by the change of the profile angle. The first variant and the second variant are may be combined.
The inventor of the present disclosure has recognized that influence can be taken on the gear geometry produced on the tool and in particular on the profile crowning produced there by a corresponding change of the settings of the axes of movement during dressing. If, however, the dresser has a modification itself, the change in the relative position between the dresser and the tool produces an unwanted stretching and/or compression of this modification on the transfer to the tool. This compression and/or stretching can, however, be at least partly compensated by the change of the profile angle of the tool in accordance with the present disclosure.
The present disclosure makes use of the fact that the same gear geometry of a workpiece can be produced with tools having a different profile angle. The profile angle, however, has an influence on the mapping of a modification of the dresser on the tool and on the mapping of a modification of the tool on the workpiece. The compression and/or stretching can therefore be reduced and minimized by the suitable selection of the profile angle. Unwanted modifications of the gear geometry arising in the machining of the workpiece can hereby be reduced.
Such a procedure in accordance with the second aspect is in particular possible in the production of symmetrical gearings of the workpiece.
The present disclosure in accordance with the second aspect is, however, also possible on the manufacture of asymmetrical gearings of the workpiece. The calculation of the profile angle which reduces or minimizes the relative profile stretching must admittedly be carried out separately on the left and right flanks. With a cylindrical tool, no complete cancellation of the stretch and/or compression is therefore possible if required. The profile angle can, however, be selected such that deviations are produced on the left and right flanks which are as small as possible in total.
The present disclosure therefore further comprises a method in accordance with the present disclosure such as was described above for producing an asymmetrical gearing of the workpiece, wherein the profile angle of the workpiece on the right and left flanks is selected such that a deviation of the gear geometry resulting on the workpiece on the left and right flanks is reduced and/or minimized overall with respect to a desired gear geometry; and/or a stretching and/or compression of a modification on the left and right flanks produced on the tool by a modified dresser is reduced or minimized overall.
In a method in accordance with the first or second aspects of the present disclosure, a tool can first be used having a cylindrical base shape, in particular a grinding worm having a cylindrical base shape.
Alternatively, however, a tool having a conical base shape can also be used. A grinding worm having a conical base shape can in particular be used.
The conical angle is optionally selected such that the gear geometry resulting on the workpiece has deviations from a desired gear geometry which are as small as possible. The inventor of the present disclosure has recognized that a further degree of freedom is provided with the conical angle by the use of a tool having a conical base shape, which degree of freedom can be used for influencing the gear geometry and in particular for avoiding unwanted modifications or for producing desired modifications.
A tool having a conical basic shape is optionally used in accordance with the second aspect, with the conical angle being selected such that a compression and/or stretching of the tool of a modification produced by a modified dresser on the tool is reduced or minimized by the change of the profile angle of the tool.
The use of a conical tool has particular advantages in the producing of an asymmetrical gearing of the workpiece. The profile angles of the tool and the conical angle can in particular be selected such that the stretching and/or compression of the modification is reduced and/or minimized on the right and left flanks.
When a tool having a conical base shape is used, provision can optionally be made that the conical angle is changed in a later dressing procedure with respect to an earlier dressing procedure.
The present disclosure is in particular used when a tool is dressed consecutively a plurality of times by the same dresser in order to produce the same respective gear geometry of a workpiece machined by the tool after every dressing procedure within the framework of the production process.
In a first application case, a dressing can already become necessary after one or more machining steps which are carried out at a single workpiece before one or more further machining steps are carried out at the same workpiece. For example, after one or more grinding strokes which are carried out at a workpiece, a dressing may become necessary before further grinding strokes are carried out at this workpiece. Such a procedure can in particular be necessary with large gearings having a large module and/or with a small tool diameter with respect to the module.
In a further application case, the present disclosure is in contrast used in a method of producing a plurality of tools, and in particular a large number of tools, with the tool being respectively dressed after the production of one or more workpieces before further workpieces are machined. Such a procedure is in particular customary in mass production in which a large number of identical workpieces are to be produced.
If a plurality or a large number of workpieces are machined in accordance with the present disclosure, deviations of the surface geometry of the respective workpieces resulting due to the machining procedure with respect to a desired geometry which is the same for all workpieces are reduced and minimized.
In a third aspect, the present disclosure comprises a method of producing a workpiece having a desired gear geometry by means of a tool suitably dressed by a modified dresser, the method comprising specifying a desired gear geometry of the workpiece; and determining a suitable profile angle of the tool and a suitable relative position between the dresser and the tool during the dressing for providing the desired gear geometry of the workpiece at least within a permitted tolerance in the machining by the tool.
As already shown above, the inventor of the present disclosure has recognized that the profile angle has an influence on the dressing procedure, but that a desired gear geometry of a workpiece can be achieved in the same way with different profile angles of the tool. In accordance with the present disclosure, the tool can thus be configured by a suitable selection of the profile angle and a suitable relative position between the dresser and the tool during dressing with a gear geometry which produces the desired gear geometry of the workpiece when machining by the tool at least within a permitted tolerance.
A compression and/or stretching of the modification of the dresser during the transfer to the tool can in particular be taken into account in the determination of the profile angle and of the relative position between the dresser and the tool.
The profile angle and the relative position between the dresser and the tool are optionally determined such that a desired compression and/or stretching of the modification of the dresser on the tool results during dressing. The method in accordance with the present disclosure can thus be used, for example, when the profile present on the dresser is to be applied to the tool in a compressed or stretched form to achieve the desired gear geometry of the workpiece.
The profile angle is, however, optionally determined such that a compression and/or stretching of the modification of the dresser on the tool resulting from the relative position between the dresser and the tool during dressing is at least partly compensated by the profile angle.
The three aspects of a method of producing a workpiece described in more detail above can each be used on their own. The individual aspects can, however, also be combined with one another.
The aspects explained in accordance with the second and third aspects with respect to a compression and/or stretching of a modification of the dresser during the dressing of the tool can in particular be combined with the aspects explained with respect to the first aspect with respect to the provision of the desired modifications of the workpiece and/or of the tool.
In addition to the above-named method of producing one or more workpieces, the present disclosure furthermore comprises a method for the modified dressing of a tool which can be used for the gear manufacturing machining of a workpiece on a dressing machine, with a modified dresser being used for dressing the tool. In accordance with the present disclosure, the axes of movement of the dressing machine are set during the dressing of the tool and/or the macrogeometry of the tool and/or of the dresser are selected such that the modification of the dresser is applied compressed or stretched by a certain amount on the tool and/or compressed or stretched by a certain amount on the workpiece. The fact is also exploited here in accordance with the present disclosure that the stretching or compression with which a modification of the dresser can be applied to the tool can be influenced by the suitable choice of the relative position between the dresser and the tool and/or of the macrogeometry of the tool or dresser. The number of starts and/or the diameter and/or the profile angle and/or the conical angle of the tool can be set or selected correspondingly with respect to the macrogeometry of the tool. The diameter of the dresser can in particular be selected suitably with respect to the macrogeometry of the dresser.
The method in accordance with the present disclosure for the modified dressing of a tool can in particular be used with a method in accordance with the present disclosure of producing one or more workpieces such as were described above.
In all of the above-shown methods in accordance with the present disclosure, the desired modification of the tool can optionally be produced at at least two rolling angles, and further optionally at at least three rolling angles, and by the setting of the axes of movement of the dressing machine. Alternatively or additionally, the relative position between the dresser and the tool during dressing can be determined such that a desired profile crowning on the tool is produced. The inventor of the present disclosure has recognized that the profile crowning of the tool can be influenced and/or the modification at two, three or four rolling angles can be set within certain limits by the suitable setting of the relative position and/or of the axes of movement of the dressing machine during dressing.
Alternatively or additionally, an association of a specific radius of the dresser with a specific radius of the tool can be specified and can be achieved by a corresponding setting of the axes of movement of the dressing machine.
The present disclosure furthermore comprises an apparatus and/or a software program in accordance with a first aspect for determining the settings of the axes of movement of the dressing machine used for the multiple dressing of a tool using the same dresser.
The apparatus and/or the software program can be used in accordance with a first variant for carrying out a method such as was described in more detail above. The apparatus and/or the software program can in particular determine suitable settings of the axes of movement of the dressing machine to carry out a method in accordance with the present disclosure such as was shown above.
In accordance with a second variant, which may be combined with a first variant, the apparatus or the software program has an input function for inputting a first tool diameter as well as a determination function for determining the setting of the axes of movement of the dressing machine to be used for the dressing of the tool with the first tool diameter. An input function for inputting a second tool diameter for which the dresser is configured is further advantageously provided. Alternatively or additionally, an input function can be provided for inputting a desired gear geometry of the workpiece or of the tool. The determination function can in particular be configured such that it determines the settings of the axes of movement to be set within the framework of the methods shown in more detail above.
In a second, independent aspect, the present disclosure further comprises an apparatus and/or a software program for determining the setting of the axes of movement of the dressing machine or the geometry of the tool to be used for producing a workpiece having a desired gear geometry by means of a tool dressed by a modified dresser having an input function for inputting a desired gear geometry of the workpiece and/or for inputting a desired stretching and/or compression of the modification of the dresser on the tool or workpiece.
In a first variant, the apparatus or the software program in accordance with the second aspect comprises a determination function for determining a suitable profile angle of the tool and a suitable relative position between the dresser and the tool during dressing for providing the desired gear geometry of the workpiece during the machining by the tool and/or for providing the desired stretching and/or compression of the modification of the dresser on the tool or workpiece.
In a second variant, the apparatus or the software program comprises a determination function for determining the setting of the axes of movement of the dressing machine during the dressing of the tool and/or the macrogeometry of the tool and/or of the dresser. In particular one or more of the following values can be determined with respect to the macrogeometry: number of starts and/or diameter and/or profile angle and/or conical angle of the tool; diameter of the dresser.
In a third variant, the apparatus and/or the software program can comprise a determination function for determining the setting of the axes of movement of the dressing machine during the dressing of the tool and/or the macrogeometry of the tool in a method such as was shown in more detail above.
Two or all three of the variants just described are optionally combined with one another within the framework of an apparatus in accordance with the present disclosure and/or of a software program in accordance with the present disclosure.
In a possible embodiment of the present disclosure, the software program can be worked through on the apparatus in accordance with the present disclosure. The software program can be stored on a data carrier or in a memory, for example. The apparatus can in particular be a computer and/or a machine control (e.g., a machine control system comprising instructions stored in non-transitory memory of the control system and executable by a processor to perform the various functions and control actions described herein). A software program in accordance with the present disclosure can optionally run thereon.
The present disclosure furthermore comprises a dressing machine having a tool holder for holding the tool to be dressed and having a dresser holder for holding the dresser used for this purpose, wherein the dresser holder has an axis of rotation and wherein the dressing machine has further axes of movement by which further degrees of freedom can be set independently of one another when dressing the tool in line contact with the dresser.
In a first variant, the dressing machine has a control which comprises an apparatus and/or a software program such as was shown in more detail above.
In a second variant, the control can have a function for carrying out the dressing steps within the framework of one of the methods in accordance with the present disclosure such as were shown in more detail above. A function for the multiple carrying out of a dressing procedure of a tool can in particular be provided having changed settings of the axes of movement of the dressing machine, wherein the control is programmed such that it changes the relative position between the dresser and the tool by a corresponding additional change of the axes of movement of the dressing machine in a later dressing procedure with respect to an earlier dressing procedure in addition to the smaller center distance resulting from the smaller tool diameter. The control can have a function for determining and/or calculating the controlling of the axes of movement.
Both variants of a dressing machine in accordance with the present disclosure are combined with one another.
The dressing machine can be a machine which is only used for dressing tools and has no additional function for machining workpieces using such tools. The dressing machine may be, however, a combination machine which allows both a machining of workpieces and the dressing.
The present disclosure further comprises a gear manufacturing machine such as was just shown. It can in particular be a combination machine on which both a gear machining of a workpiece can be carried out by a tool and the dressing of the tool can be carried out by a dresser. Alternatively or additionally, the gear manufacturing machine in accordance with the present disclosure can also comprise an apparatus and/or a software program such as was shown above. In this respect, the manufacturing machine and the dressing machine can optionally share individual holders or axes of movement or a plurality of holders or axes of movement.
The gear manufacturing machine optionally has a workpiece holder and a tool holder provided in addition to the tool holder of the dressing machine as well as a gear manufacturing machining control for controlling the workpiece holder and the tool holder for carrying out a gear manufacturing machining. The gear manufacturing machining control is in particular programmed such that it carries out a method in accordance with the present disclosure, in particular in an automated manner. The gear manufacturing machining control and the control which controls the dressing processes are optionally configured such that a method in accordance with the present disclosure can be carried out in an automated manner.
The methods in accordance with the present disclosure are furthermore optionally carried out using an apparatus in accordance with the present disclosure and/or a software program in accordance with the present disclosure and/or a dressing machine in accordance with the present disclosure and/or a gear-manufacturing machine in accordance with the present disclosure.
The gear manufacturing machining in accordance with the present disclosure is optionally a generating machining method, in particular a generating grinding method. An axial generating method or a diagonal generating method are optionally used.
The tool which is dressed or used in accordance with the present disclosure is optionally a grinding worm. A profile roller dresser or a form roller is optionally used as the dresser in accordance with the present disclosure.
The method in accordance with the present disclosure and the apparatus or tools in accordance with the present disclosure are optionally configured such that an involute gearing is produced in accordance with the present disclosure on the workpiece.
In accordance with the present disclosure, the relative position of the dresser to the tool during dressing with line contact can be specifically set such that the contact line between the dresser and the tool on the dresser is displaced in order hereby to influence the active profile transferred to the tool along the contact line. The desired modification on the tool is hereby produced. The crowning along the contact line and thus the profile crowning can in particular be set or changed.
The present disclosure will now be explained in more detail with reference to embodiments and to drawings.